Multi-format audio/video production system

ABSTRACT

An audio/video production system facilitates professional quality image manipulation and editing using an enhanced general-purpose hardware. A program input may be translated into any of a variety of graphics or television formats, including NTSC, PAL, SECAM and HDTV, and stored as data-compressed images, using any of several commercially available methods such as Motion JPEG, MPEG, etc. While being processed, the images may be re-sized to produce a desired aspect ratio or dimensions using conventional techniques such as pixel interpolation. Frame rate conversion to and from conventional formats is performed by using the techniques employed for film-to-NTSC and film-to-PAL transfers, or by inter-frame interpolation, all well known in the art. By judicious selection of the optimal digitizing parameters, the system allows a user to establish an interrelated family of aspect ratios, resolutions, and frame rates, yet remain compatible with currently available and planned graphics and television formats.

REFERENCE TO RELATED APPLICATIONS

This application is a continuation-in-part of U.S. patent applicationSer. No. 08/050,861, filed Apr. 21, 1993.

FIELD OF THE INVENTION

This invention relates generally to video production, photographic imageprocessing, and computer graphics design, and, more particularly, to amulti-format video production system capable of professional qualityediting and manipulation of images intended for television and otherapplications, including HDTV programs.

BACKGROUND OF THE INVENTION

As the number of television channels available through various programdelivery methods (cable TV, home video, broadcast, etc.) continues toproliferate, the demand for programming, particularly high-qualityHDTV-format programming, presents special challenges, both technical andfinancial, to program producers. While the price of professional editingand image manipulation equipment continues to increase, due to the highcost of research and development and other factors, general-purposehardware, including personal computers, can produce remarkable effectsat a cost well within the reach of non-professionals, even novices. As aresult, the distinction between these two classifications of equipmenthas become less well defined.

The parent to this application, for example, describes a videoproduction system which integrates equipment supplied by variousmanufacturers, enabling a consumer to produce and edit video materialusing an enhanced personal computer. An adapter unit interfaced to eachcamera in use with the system connects to a camera interface module, andeach camera interface module, in turn, feeds a computer interface unit.These computer interface units communicate with a personal computer overa standard interconnect, allowing an operator to control the variouscameras while viewing individual video programs which appear in separate“windows” on the computer monitor.

This related invention solves many of the problems associated withcombining commercially available hardware to create an economicalpersonal-computer-based system capable of very high quality audio/videoproduction. However, the variety of available and planned programstandards and delivery methods places further demands on videoproduction equipment, including the editing and manipulation of imagesnot only from a variety of sources, but in differing pixel formats,frame rates, and so forth. Although general-purpose PC-based equipmentmay never allow professional-style rendering of images at fullresolution in real-time, each new generation of microprocessors enablesprogressively faster, higher-resolution applications. In addition, asthe price of memory circuits and other data storage hardware continuesto fall, the capacity of such devices has risen dramatically, therebyimproving the prospects for enhancing PC-based image manipulationsystems for such applications.

In terms of dedicated equipment, attention has traditionally focused onthe development of two kinds of professional image-manipulation systems:those intended for the highest quality levels to support film effects,and those intended for television broadcast to provide “full 35 mmtheatrical film quality,” within the realities and economics of presentbroadcasting systems. Conventional thinking holds that 35 mm theatricalfilm quality is equivalent to 1200 or more lines of resolution, whereascamera negatives present 2500 or more lines. As a result, image formatsunder consideration have been directed towards video systems having 2500or more scan lines for high-level production (such as the Kodak“Electronic Intermediate” system described by Hunt et al.), withhierarchies of production, HDTV broadcast, and NTSC and PAL compatiblestandards which are derived by down-converting these formats. Severaltechniques have been described, including those of Bretyl (“3×NTSC‘Leapfrog’ Production Standard for HDTV”, SMPTE Journal, March 1989),Demos (“An Example Hierarchy of Formats for HDTV”, SMPTE Journal,September 1992), and Lim (“A Proposal for an HDTV/ATV Standard withMultiple Transmission Formats”, SMPTE Journal, August 1993). Mostproposals employ progressive scanning, although interlace is consideredan acceptable alternative as part of an evolutionary process. Inparticular, Demos addresses the important issue of compatibility tocomputer-graphics-compatible formats, although he begins with an1152-line format, and only considers progressive scanning. And, aspointed out by Thorpe et al., progressive scanning also has drawbacks,and as shown by Kaiser et al. (“Resolution Requirements for HDTV BasedUpon the Performance of 35 mm Motion-Picture Films for TheatricalViewing”, SMPTE Journal, June 1985), even 35 mm theatrical film qualityis a misnomer since the realities of mechanical projection systemsrestrict the typical screen display to less than 700 TV lines/pictureheight.

Current technology directions in computers and image processing shouldallow production equipment based upon fewer than 1200 scan lines, withpicture expansions to create a hierarchy of upward-converted formats fortheatrical projection, film effects, and film recording. In additiongeneral-purpose hardware enhancements should be capable of addressingthe economic aspects of production, a subject not considered in detailby any of the available references.

SUMMARY OF THE INVENTION

The present invention takes advantage of general-purpose hardware wherepossible to provide an economical multi-format video production system.In the preferred embodiment, specialized graphics processingcapabilities are included in a high-performance personal computer orworkstation, enabling the user to edit and manipulate an input videoprogram and produce an output version of the program in a final formatwhich may have a different frame rate, pixel dimensions, or both. Aninternal production format is chosen which provides the greatestcompatibility with existing and planned formats associated with standardand widescreen television, high-definition television, and film. Forcompatibility with film, the frame rate of the internal productionformat is preferably 24 fps. Images are re-sized by the system to largeror smaller dimensions so as to fill the particular needs of individualapplications, and frame rates are adapted by inter-frame interpolationor by traditional schemes, including “3:2 pull-down” for 24-to-30 fpsconversions, or by manipulating the frame rate itself for 24 to 25 fpsfor a PAL-compatible display. The enhancement to a general-purposeplatform preferably takes the form of a graphics processor connected toreceive a video signal in an input format. The processor comprises aplurality of interface units, including a standard/widescreen interfaceunit operative to convert the video program in the input format into anoutput signal representative of a standard/widescreen formatted image,and output the signal to an attached display device. A high-definitiontelevision interface unit is operative to convert the video program inthe input format into an output signal representative of anHDTV-formatted image, and output the signal to the display device. Acentralized controller in operative communication with the video programinput, the graphics processor, and an operator interface, enablescommands entered by an operator to cause the graphics processor toperform one or more of the conversions using the television interfaces.The present invention thus encourages production at relatively low pixeldimensions to make use of lower-cost general-purpose hardware and tomaintain high signal-to-noise, then subsequently expands the result intoa higher-format final program. This is in contrast to competingapproaches, which recommend operating at higher resolution, thendown-sizing, if necessary, to less expensive formats which has led tothe high-cost, dedicated hardware, the need for which the presentinvention seeks to eliminate.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1A-1D show the preferred and alternative image aspect ratios inpixels;

FIG. 2A shows the mechanical design for a digital camera configured toexecute the preferred embodiment;

FIG. 2B shows a digital camera configured to execute the preferredembodiment for several different formats;

FIG. 2C shows a low-cost digital camera configured to execute thepreferred embodiment for several different formats;

FIG. 3 shows a functional diagram for disk-based video recording;

FIG. 4 shows the components comprising the multi-format audio/videoproduction system;

FIG. 5 depicts an approach for reducing the chrominance bandwidth ofwide-band analog RGB output signals without decreasing the luminanceresolution;

FIG. 6 shows the inter-relationship of the multi-format audio/videoproduction system to many of the various existing and planned videoformats; and

FIG. 7 shows the implementation of a complete television productionsystem, based on one possible choice for image sizes and aspect ratios.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

The present invention builds upon and extends certain of the conceptsintroduced in the parent to this application, “Personal-Computer-BasedVideo Production System.” Ser. No. 08/050,861 filed Apr. 21, 1993. Thesystem described in that application allows an operator to controlequipment supplied by various manufacturers at a centralized personalcomputer to produce, edit and record a video program. Each camera to beused with the system described in this previously filed applicationfeeds a signal to the personal computer through a custom adapter unit,cable and camera interface module the latter containing cablecompensation and gain circuitry. The interface modules feed a commonvideo switcher, audio mixer and display means, all of which may beprovided by a variety of sources, including different manufacturers. Inthe preferred embodiment, the display is the monitor of a programmedpersonal computer, and computer interface modules connected between eachcamera interface module and the computer allow video images generated bythe cameras to appear in different windows on the computer monitor.Control signals entered at the computer are routed to the cameras inorder to control their functioning.

The present invention is primarily concerned with a different butrelated aspect of facilitating professional quality audio/videoproduction; namely, the conversion of disparate graphics or televisionformats, including requisite frame-rate conversions, to establish aninterrelated family of aspect ratios, resolutions, and frame rates,while remaining compatible with available and future graphics/TVformats. These formats include images of pixel dimensions capable ofbeing displayed on currently available multi-scan computer monitors, andcustom hardware will be described whereby frames of higher pixel-countbeyond the capabilities of these monitors may be viewed. Images arere-sized by the system to larger or smaller dimensions so as to fill theparticular needs of individual applications, and frame rates are adaptedby inter-frame interpolation or by traditional schemes such as using“3:2 pull-down” (for 24 to 30 frame-per-second film-to-NTSC conversions)or by speeding up the frame rate itself (as for 24 to 25 fps for PALtelevision display). The resizing operations may involve preservation ofthe image aspect ratio, or may change the aspect ratio by “cropping”certain areas, by performing non-linear transformations, such as“squeezing” the picture, or by changing the vision center for “panning,”“scanning” and so forth. Inasmuch as film is often referred to as “theuniversal format,” primarily because 35-mm film equipment isstandardized and used throughout the world, the preferred internal or“production” frame rate is preferably 24 fps. This selection also has anadditional benefit, in that the 24 fps rate allows the implementation ofcameras having greater sensitivity than at 30 fps, which is even morecritical in systems using progressive scanning, for which the rate willbe 48 fields per second vs. 60 fields per second in some other proposedsystems.

The image dimensions chosen allow the use of conventional CCD-typecameras, but the use of digital processing directly through the entiresignal chain is preferred, and this is implemented by replacing thetypical analog RGB processing circuitry with fully digital circuitry.Production effects may be conducted in whatever image size isappropriate, and then re-sized for recording. Images are recorded bywriting the digital data to storage devices employing removablehard-disk drives, disk drives with removable media, optical ormagneto-optical based drives, or tape-based drives, preferably incompressed-data form. As data rates for image processing andreading-from or writing-to disk drives increase, many processes thatcurrently require several seconds will soon become attainable inreal-time, which will eliminate the need to record film frames at slowerrates. Other production effects, such as slow-motion or fast-motion maybe incorporated, and it is only the frame rates of these effects thatare limited in any way by the technology of the day. In particular,techniques such as non-linear-editing, animation, and special-effectswill benefit from the implementation of this system. In terms of audio,the data rate requirements are largely a function of sound quality. Theaudio signals may be handled separately, as in an “interlocked” orsynchronized system for production, or the audio data may be interleavedwithin the video data stream. The method selected will depend on thetype of production manipulations desired, and by the limitations of thecurrent technology.

Although a wide variety of video formats and apparatus configurationsare applicable to the present invention, the system will be described interms of the alternatives most compatible with currently availableequipment and methods. FIG. 1A illustrates one example of a compatiblesystem of image sizes and pixel dimensions. The selected frame rate ispreferably 24 per second (2:1 interlaced), for compatibility with filmelements; the selected picture dimension in pixels is preferably1024×576 (0.5625 Mpxl), for compatibility with the 16:9 “widescreen”aspect ratio anticipated for all HDTV systems, and the conventional 4:3aspect ratio used for PAL systems [768×576 (0.421875 Mpxl)]. Allimplementations preferably rely on square pixels, though other pixelshapes may be used. Re-sizing (using the well known, sophisticatedsampling techniques available in many image-manipulation softwarepackages or, alternatively, using hardware circuitry described hereinbelow) to 2048×1152 (2.25 Mpxl) provides an image suitable for HDTVdisplays or even theatrical projection systems, and a further re-sizingto 4096×2304 (9.0 Mpxl) is appropriate for even the most demandingproduction effects. Images may be data compressed 5:1 for 16:9“wide-screen” TV frames, or 10:1 for HDTV; the data files may then bestored on conventional disk drives, requiring only approximately 8.1MB/sec for wide-screen frames in RGB, and only 16.1 MB/sec for HDTVframes in RGB.

An alternative embodiment of the invention is shown in FIG. 1B. In thiscase, the user would follow a technique commonly used in filmproduction, in which the film is exposed as a 4:3 aspect ratio image.When projected as a wide-screen format image, the upper and lower areasof the frame may be blocked by an aperture plate, so that the imageshows the desired aspect ratio (typically 1.85:1 or 1.66:1). If theoriginal image format were recorded at 24 frames per second, with a 4:3ratio and with a dimension in pixels of 1024×768, all imagemanipulations would preserve these dimensions. Complete compatibilitywith the existing formats would result, with NTSC and PAL imagesproduced directly from these images by re-scaling, and theaforementioned wide-screen images would be provided by excluding 96 rowsof pixels from the top of the image and 96 rows of pixels from thebottom of the image, resulting in the 1024×576 image size as disclosedabove. The data content of each of these frames would be 0.75 Mpxls, andthe data storage requirements disclosed above would be affectedaccordingly.

Another embodiment of the invention is depicted in FIG. 1C. In thisalternative, the system would follow the image dimensions suggested inseveral proposed digital HDTV formats under consideration by theAdvanced Television Study Committee of the Federal CommunicationsCommission. The format to be adopted is expected to assume a wide-screenimage having dimensions of 1280×720 pixels. Using these image dimensions(but at 24 fps with 2:1 interlace), compatibility with the existingformats would be available, with NTSC and PAL images derived from thisframe size by excluding 160 columns of pixels from each side of theimage, thereby resulting in an image having a dimension in pixels of960×720. This new image would then be re-scaled to produce images havingpixel dimensions of 640×480 for NTSC, or 768×576 for PAL; thecorresponding wide-screen formats would be 854×480 and 1024×576,respectively. In this case, an image having a dimension in pixels of1280×720 would contain 0.87890625 Mpxl, with 1,000 TV lines ofresolution; furthermore, the systems under evaluation by the ATSC of theFCC also assume a decimation of the two chrominance signals, with detailof only 640×360 pixels retained. The data storage requirements disclosedabove would be affected accordingly. The development path to 24 fps withprogressive scanning is both well-defined and practical, as is the useof the previously described methods to produce images having a dimensionin pixels of 2048×1152.

A further alternative embodiment of the invention is shown in FIG. 1D.As with the system described with reference to FIG. 1B, the user followsthe technique commonly used in film production, wherein the film isexposed as a 4:3 aspect ratio image. When projected as a wide-screenformat image, the upper and lower areas of the frame area again blockedby an aperture plate, so that the image shows the desired aspect ratio(typically 1.85:1 or 1.66:1). For an original image format recorded at24 frames per second, with 4:3 ratio and with pixel dimensions of1280×960, all image manipulations preserve these dimensions. Completecompatibility with the existing formats results, with NTSC and PALimages produced directly from these images by rescaling, and theaforementioned wide-screen images are provided by excluding 120 rows ofpixels from the top of the image and 120 rows of pixels from the bottomof the image, thereby resulting in the 1280×720 image size as describedabove. The data content of each of these frames is 0.87890625 Mpxls, andthe data storage requirements disclosed above are affected accordingly.

Currently available CCD elements for PAL/HDTV dual-use cameras provide600,000 pixels, typically as arrays of 1024×592 or similar dimensions.By modifying the camera circuitry, the optical and CCD-driver circuitrymay be adapted for use by the present invention, thereby allowing foreconomical implementation of the preferred configuration. FIG. 2A showsa camera as modified for this application. A lens 2 and viewfinder 4 aremounted upon the body of the camera frame. The usual optical-splitter,CCD-sensors and driver circuitry, and the inventive all-digital signalprocessing circuitry are located at 6, with optional battery-packcapability at 10. The various analog and digital output signals and anyinput audio, video or control signals, all shown generally at 16, areinterfaced through appropriate connectors disposed on the rear-panel 12and sub-panel 14. Provisions are included as shown for the input ofanalog audio signals, and for the output of both analog and digitalaudio signals. Preferably fiber-optic cabling is employed to carry thenecessary signals. Internal video recording facilities 8 are describedherein below.

Conventional CCD-element cameras of the type described above produceimages of over 800 TV Lines horizontal Luminance (Y) resolution, with asensitivity of 2,000 lux at f8, and with a signal-to-noise ratio of 62dB. However, typical HDTV cameras, at 1,000 TV Lines resolution and withsimilar sensitivity, produce an image with only a 54 dB signal-to-noiseratio, due to the constraints of the wideband analog amplifiers and thesmaller physical size of the CCD-pixel-elements. By employing the moreconventional CCD-elements in the camera systems of this invention, andby relying upon the computer to create the HDTV-type image by imagere-sizing, the improved signal-to-noise ratio is retained. In thepractical implementation of cameras conforming to this new designapproach, there will be less of a need for extensive lightingprovisions, which in turn, means less demand upon the power generatorsin remote productions, and for AC-power in studio applications.

FIG. 2B shows the configuration of a digital video camera implementingthe preferred embodiment of the invention. A lens assembly 20 is coupledto an optical beam-splitter 22, which focuses red, green and blue imagesonto CCD-elements 24a, 24b, and 24c, respectively. The output signalsfrom each of these CCD-elements is directed to its respectiveanalog-to-digital converter 26a, 26b, and 26c. The output of these threeanalog-to-digital converters is carried to digital signal processor 28,which provides digital signal outputs 34, configured as RGB, Y/R-Y/B-Y,YUV, YIQ, or any other format, as desired. In addition, these digitaloutput signals are also provided to digital-to-analog converters 30a,30b, and 30c, and from these converters to the analog signal processor32. This processor provides the analog output signals 36 in the formatdesired, including the RGB, Y/R-Y/B-Y, YUV, YIQ, or other formats asdescribed above, or additionally, in the composite video or Y/C formatscommonly employed in conventional video production equipment and VTRs. Afiber-optic interface 38 accepts digital video signals from the digitalsignal processor 28 and provides these signals through the fiber-opticcable 40. Control signals are received from the fiber-optic cable 40 andcarried through to the digital signal processor 28; other cameraoperational and status signals, such as tally signals, remote lenscontrols, return video signals, and so forth, are carried in the reversedirection along this same path from the digital signal processor 28,through the fiber-optic interface 38, to the fiber-optic cable 40.

In practice, the implementation of this design using three600,000-element CCDs and the commonly employed technique of thespatial-shift for the green CCD-element (as described below) willproduce Y/R-Y/B-Y signals with 800 TV lines of resolution, and willprovide a luminance bandwidth of 15 MHz and a Chrominance bandwidth of7.5 MHz. The RGB video signal outputs will provide a full 15 MHzbandwidth for each channel, and the camera will be suitable for theconventional/widescreen application described herein. However, for HDTVproduction, a higher performance level is desired. Accordingly, thesystem of FIG. 2B, as described above, is implemented with three of thelatest 2.4 Mpxl CCD-elements, providing images of pixel dimension2048×1152. In the digital realm, the resultant image is 6.75 MB perframe, and the data rate of 162 MB/sec is subjected to a 10:1data-compression to 16.2 MB/sec for recording and production. Theresulting image exhibits over 1,000 TV lines of resolution, againrelying upon the spatial shift of the green CCD-element as describedherein below. For Y/R-Y/B-Y signals, the Luminance bandwidth will be 60MHz, and the Chrominance bandwidth will be 30 MHz. The RGB video signaloutputs will provide a full 60 MHz bandwidth for each channel. In thiscase, it will be possible to re-size the picture image to be as large as8192×4608, which would even enable the system to be used for specialoptical effects, or with other specialized film formats, such as IMAXand those employing 65 mm camera negatives.

A more economical alternative implementation of the camera system isshown in FIG. 2C. In this case, the camera employs a single 1.2 MpxlCCD-element, using color filters to produce the color signals. As shown,the camera lens assembly 42 is coupled to the color-filter assembly 44.The Luminance signal 46, and the Chrominance signals 48 are provided tothe inputs of their respective analog-to-digital converters 50 and 52.The outputs of these converters are provided to the digital signalprocessor 54, which produces the digital video output signals 62. Thesesignals may be in any of a number of alternative formats, including, forexample, RGB, Y/R-Y/B-Y, YUV, or YIQ. These signals are additionallyprovided to digital-to-analog converters 56a, 56b, and 56c,respectively, and then to the analog signal processor 60, which providesanalog output signals 64 in the format desired, including the RGB,Y/R-Y/B-Y, YUV, YIQ, or other formats as described above, oradditionally in the composite video or Y/C formats commonly employed inconventional video production equipment and VTRs. In this case, theimage size will be 1024×576 for the luminance channel (producingapproximately 600 TV Lines of resolution), and 512×576 for each of thechrominance channels. In this case, it is not possible to introduce thegreen spatial-shift approach, because only a single CCD-element isemployed. However, the luminance channel bandwidth achieved will be 15MHz, and the chrominance channel bandwidth will be 7.5 MHz.

In CCD-based cameras, it is a common technique to increase the apparentresolution by mounting the red and blue CCD-elements in registration,but offsetting the green CCD-element by one-half pixel widthhorizontally. In this case, picture information is in-phase, butspurious information due to aliasing is out-of-phase. When the threecolor signals are mixed, the picture information is intact, but most ofthe alias information will be canceled out. This technique willevidently be less effective when objects are of solid colors, so it isstill the usual practice to include low-pass optical filters mounted oneach CCD-element to suppress the alias information. In addition, thistechnique cannot be applied to computer-based graphics, in which thepixel images for each color are always in registration. However, ingeneral-use video, the result of the application of this spatial-shiftoffset is to raise the apparent luminance (Y) horizontal resolution toapproximately 800 television lines.

The availability of hard-disk drives of progressively higher capacityand data transmission rates is allowing successively longer and higherresolution image displays in real-time. At the previously cited datarates, wide-screen frames would require 486 MB/min, so that currentlyavailable 10 GB disk drives will store more than 21 minutes of video.When the anticipated 100 GB disk drives (2.5-inch or 3.5-inch disksusing Co-Cr, barium ferrite, or other high-density recording magneticmaterials) become available, these units will store 210 minutes, or 3½hours of video. For this application, a data storage unit 8 is providedto facilitate editing and production activities, and it is anticipatedthat these units would be employed in much the same way as videocassettes are currently used in Betacam and other electronic newsgathering (ENG) cameras and in video productions. This data storage unitmay be implemented by use of a magnetic, optical, or magneto-opticaldisk drive with removable storage media, or by a removable disk-driveunit, such as those based on the PCMCIA standards. Although PCMCIA mediaare 1.8-inches in dimension, alternative removable media storage unitsare not restricted to this limit, and could employ larger media, such as2.5-inch or 3.5-inch disks; this, in turn, will lead to longer durationprogram data storage, or could be applied to lower ratios of datacompression or higher-pixel-count images within the limits of the samesize media.

FIG. 3 shows the functional diagram for the storage-device-based digitalrecorder employed in the video camera, or separately in editing andproduction facilities. As shown, a removable hard disk drive 70 isinterfaced through a bus controller 72; in practice, alternative methodsof storage such as optical or magneto-optical drives could be used,based on various interface bus standards such as SCSI-2 or PCMCIA. Thisdisk drive system currently achieves data transfer rates of 20 MB/sec,and higher rates on these or other data storage devices, such ashigh-capacity removable memory modules, is anticipated. Themicroprocessor 74 controls the 64-bit or wider data bus 80, whichintegrates the various components. Currently available microprocessorsinclude the Alpha 21064 by Digital Equipment Corporation, or the MIPSR4400 by MIPS Technologies, Inc.; future implementations would rely onthe already announced P6 by Intel Corp. or the PowerPC 620, which iscapable of sustained data transfer rates of 100 MB/sec. Up to 256 MB ofROM, shown at 76, is anticipated for operation, as is 256 MB or more ofRAM, shown at 78. Current PC-based video production systems are equippedwith at least 64 MB of RAM, to allow sophisticated editing effects. Thegraphics processor 82 represents dedicated hardware that performs thevarious manipulations required to process the input video signals 84 andthe output video signals 86; although shown using an RGB format, eitherthe inputs or outputs could be configured in alternative formats, suchas Y/R-Y/B-Y, YIQ, YUV or other commonly used alternatives. Inparticular, while a software-based implementation of the processor 82 ispossible, a hardware-based implementation preferred, with the systememploying a compression ratio of 5:1 for the conventional/widescreensignals (“NTSC/PAL/Widescreen”), and a 10:1 compression ratio for HDTVsignals (2048×1152, as described herein above). An example of one of themany available options for this data compression is the currentlyavailable Motion-JPEG system. Image re-sizing may alternatively beperformed by dedicated microprocessors, such as the gm865×1 or gm833×3by Genesis Microchip, Inc. Audio signals may be included within the datastream, as proposed in the several systems for digital televisiontransmission already under evaluation by the Federal CommunicationsCommission, or by one of the methods available for integrating audio andvideo signals used in multi-media recording schemes, such as theMicrosoft “.AVI” (Audio/Video Interleave) file format. As analternative, an independent system for recording audio signals may beimplemented, either by employing separate digital recording provisionscontrolled by the same system and electronics, or by implementingcompletely separate equipment external to the camera system describedherein above.

FIG. 4 shows the components that comprise a multi-format audio/videoproduction system. As in the case of the computer disk-based recordingsystem of FIG. 3, an interface bus controller 106 provides access to avariety of storage devices, preferably including an internal hard-diskdrive 100, a tape-back-up drive 102, and a hard-disk drive withremovable media or a removable hard-disk drive 104. The interface busstandards implemented could include, among others, SCSI-2 or PCMCIA.Data is transmitted to and from these devices under control ofmicroprocessor 110. Currently, data bus 108 would operate as shown as64-bits wide, employing microprocessors such as those suggested for thecomputer-disk-based video recorder of FIG. 3; as higher-poweredmicroprocessors become available, such as the PowerPC 620, the data busmay be widened to accommodate 128 bits, and the use of multiple parallelprocessors may be employed, with the anticipated goal of 1,000 MIPS perprocessor. Up to 256 MB of ROM 112 is anticipated to support therequisite software, and at least 1,024 MB of RAM 114 will allow for thesophisticated image manipulations, inter-frame interpolation, andintra-frame interpolation necessary for sophisticated productioneffects, and for conversions between the various image formats.

A key aspect of the system is the versatility of the graphics processorshown generally as 116. Eventually, dedicated hardware will allow thebest performance for such operations as image manipulations andre-scaling, but it is not a requirement of the system that it assumethese functions. Three separate sections are employed to process thethree classifications of signals. Although the video input and outputsignals described herein below are shown, by example, as RGB, anyalternative format for video signals, such as Y/R-Y/B-Y, YIQ, YUV, orother alternatives may be employed as part of the preferred embodiment.One possible physical implementation would be to create a separatecircuit board for each of the sections as described below, andmanufacture these boards so as to be compatible with existing or futurePC-based electrical and physical interconnect standards.

A standard/widescreen video interface 120, intended to operate withinthe 1024×576 or 1024×768 image sizes, accepts digital RGB signals forprocessing and produces digital RGB outputs in these formats, as showngenerally at 122. Conventional internal circuitry comprising D/Aconverters and associated analog amplifiers are employed to convert theinternal images to a second set of outputs, including analog RGB signalsand composite video signals. These outputs may optionally be supplied toeither a conventional multi-scan computer video monitor or aconventional video monitor having input provisions for RGB signals (notshown). A third set of outputs supplies analog Y/C video signals. Thegraphics processor may be configured to accept or output these signalsin the standard NTSC, PAL, or SECAM formats, and may additionally beutilized in other formats as employed in medical imaging or otherspecialized applications, or for any desired format for computergraphics applications. Conversion of these 24 frame-per-second images tothe 30 fps (actually, 29.97 fps) NTSC and 25 fps PAL formats may beperformed in a similar manner to that used for scanned film materials,that is to NTSC by using the conventional 3:2 “pull-down”field-sequence, or to PAL by running the images at the higher 25 fpsrate. For other HDTV frame rates, aspect ratios, and line rates,intra-frame and inter-frame interpolation and image conversions may beperformed by employing comparable techniques well known in the art ofcomputer graphics and television.

The management of 25 fps (PAL-type) output signals in a systemconfigured for 24 fps production applications presents technical issueswhich must be addressed, however. Simple playback of signals to producePAL output is not a serious problem, since any stored video images maybe replayed at any frame rate desired, and filmed material displayed at25 fps is not objectionable. Indeed, this is the standard method forperforming film-to-tape transfers used PAL- and SECAM-televisioncountries. However, it is not practical to produce both PAL and NTSCsignals concurrently from a single source running at 24 fps.Simultaneous output of both NTSC and film-rate images is performed byexploiting the 3:2 field-interleaving approach: 5×24=2×60; that is, twofilm frames are spread over five video fields. This makes it possible toconcurrently produce film images at 24 fps and video images at 30 fps.The difference between 30 fps and the exact 29.97 fps rate of NTSC maybe palliated by slightly modifying the system frame rate to 23.976 fps.This is not noticeable in normal film projection, and is an acceptabledeviation from the normal film rate. However, if the system frame rateis adjusted to 25 fps to produce PAL or SECAM output, there is noconvenient technique to produce 30 fps NTSC concurrently, unlessmultiple-frame storage with motion-interpolation is employed, whichtends to create udesirable artifacts in the image produced. Commercialstandards-converters are available to perform this function, however,from companies such as Snell & Wilcox. This system is primarily directedtowards production of video-based film and high-definition TV images,for which 24 fps and 30 fps, respectively, are the established framerate for film and the proposed frame rate for HDTV (in NTSC-countries).The conversion to 25 fps is performed without difficulties in anyapplication in which there is no requirement for the simultaneousproduction of images at other frame rates. Using this approach, theadjustment of frame rates for playback of the images by the system issufficient for all of the normal production applications.

An HDTV video interface 124, intended to operate within the 2048×1152 or2048×1536 image sizes (with re-sizing as necessary), accepts digital RGB(or alternative) signals for processing and produces digital outputs inthe same image format, as shown generally at 126. As is the case for theStandard/Widescreen interface 120, conventional internal circuitrycomprising D/A converters and associated analog amplifiers are employedto convert the internal images to a second set of outputs, for analogRGB signals and composite video signals. In normal practice, theseoutputs would have a full 15 MHz bandwidth for each of the three R, G,and B signals. However, by applying the technique shown in FIG. 5, it ispossible to produce a signal having a 15 MHz luminance bandwidth, butonly 7.5 MHz chrominance bandwidth. In effect, the circuitry shownsimulates the results of applying a 4:2:2 sampling technique (as iscommonly used in the Television Industry) without employing the step ofcreating the two chrominance components for sub-sampling, for example, Iand Q for NTSC, U and V for PAL, or R-Y and B-Y. As shown, analog R, G,and B signals 140a, 140b, and 140c are supplied to low-pass filters142a, 142b, and 142c, respectively, which are designed to removefrequencies above 7.5 MHz. In addition, these R, G, and B signals areapplied to a standard RGB-to-Y matrix 144 to produce a standardluminance Y signal, which is carried to high-pass filter 146 which isdesigned to remove signal components below 7.5 MHz. This filteredluminance signal is then carried to a standard Y-to-RGB Matrix 148, inwhich the signal is proportionately split into R, G, and B components,and then supplied to mixers 150a, 150b, and 150c, wherein the luminancesignal is mixed with R, G, and B signals from the three low-pass filters142a, 142b, and 142c. The resulting analog R, G, and B outputs now havethe full 15 MHz luminance bandwidth, but the chrominance bandwidth hasbeen limited to 7.5 MHz. It is anticipated that different applicationsmay require modification of the luminance bandwidth from 15 MHz, and ofthe chrominance bandwidth from 7.5 MHz, and the application of thesetechniques should be considered to be within the scope of thisinvention.

The third section of the graphics processor 116 shown in FIG. 4 is thefilm output video interface 128, which comprises a special set of videooutputs 130 intended for use with devices such as laser film recorders.These outputs are preferably configured to provide a 4096×2304 or4096×3072 image size from the image sizes employed internally, usingre-sizing techniques discussed herein as necessary for the formatconversions. Although 24 fps is the standard frame rate for film, someproductions employ 30 fps, especially when used with NTSC materials, andthese alternative frame rates, as well as alternative image sizes, areanticipated as suitable applications of the invention.

Several additional features of this system are disclosed in FIG. 4. Thegraphics processor includes a special output 132 for use with a colorprinter. In order to produce the highest quality prints from the screendisplay it is necessary to adjust the printer resolution to match theimage resolution, and this is automatically optimized by the graphicsprocessor for the various image sizes produced by the system. Inaddition, provisions are included for an image scanner 134, which may beimplemented as a still image scanner or a film scanner, thereby enablingoptical images to be integrated into the system. An optional audioprocessor 136 includes provisions for accepting audio signals in eitheranalog or digital form, and outputting signals in either analog ordigital form, as shown in the area generally designated as 138. Formaterials including audio intermixed with the video signals as describedherein above, these signals are routed to the audio processor forediting effects and to provide an interface to other equipment.

It is important to note that although FIG. 4 shows only one set of eachtype of signal inputs, the system is capable of handling signalssimultaneously from a plurality of sources and in a variety of formats.Depending on the performance level desired and the image sizes and framerates of the signals, the system may be implemented with multiple harddisk units and bus controllers, and multiple graphics processors,thereby allowing integration of any combination of live camera signals,prerecorded materials, and scanned images. Improved data compressionschemes and advances in hardware speed will allow progressively higherframe rates and image sizes to be manipulated in real-time.

FIG. 6 shows the inter-relationship of the various film and videoformats compatible with the invention, though not intended to beinclusive of all possible implementations. In typical operations, themulti-format audio/video production system 162 would receive film-basedelements 160 and combine them with locally produced materials already inthe preferred internal format of 24 frames-per-second. In practice,materials May be converted from any other format including video at anyframe rate or standard. After the production effects have beenperformed, the output signals may be configured for any use required,including, but not limited to, HDTV at 30 fps shown as 164,NTSC/widescreen at 30 fps shown as 166, PAL-SECAM/widescreen at 25 fpsshown as 170, or HDTV at 25 fps shown as 172. In addition, outputsignals at 24 fps are available for use in a film-recording unit 168.

FIG. 1A shows the preferred family of aspect ratios and image framesizes in pixels. The internal production storage format 180 has framesize 1024×576 with aspect ratio 16:9, and may be trimmed of side panelsto use as a 768×576 image frame with aspect ratio of 4:3 in conventionaltelevision formats such as NTSC or PAL. After a 2:1 expansion/re-sizing,the HDTV format 182 is available, with frame size 2048×1152 and the same16:9 aspect ratio. A further 2:1 expansion/re-sizing to the film format184, with frame size 4096×2304 and the same 16:9 aspect ratio, allowsfor recording of film via currently available technology.

FIG. 1B shows an alternative family of aspect ratios and image framesizes in pixels. The internal production storage format 190 has framesize 1024×768 with aspect ratio 4:3 as employed in conventionaltelevision formats such as NTSC, or PAL, and may be trimmed of top andbottom panels to use as a 1024×576 image frame with aspect ratio of16:9. After a 2:1 expansion/resizing, the intermediate format 192 isavailable, with frame size 2048×1536 and the same 4:3 aspect ratio. Afurther 2:1 expansion/re-sizing to the alternative Film format 194, withframe size 4096×3072 and the same 4:3 aspect ratio, allows for recordingof film via currently available technology.

FIG. 1C shows another alternative family of aspect ratios and imageframe sizes in pixels, based on compatibility with several of theproposed digital HDTV formats. The internal production storage format200 has frame size 1280×720 with aspect ratio 16:9, and may be trimmedof side panels to use as a 960×720 image frame with aspect ratio of 4:3in conventional television formats such as NTSC or PAL. After a 2:1expansion/re-sizing, the HDTV format 202 is available, with frame size2560×1440 and the same 16:9 aspect ratio. A further 2:1expansion/re-sizing to the film format 204, with frame size 5120×2880and the same 16:9 aspect ratio, allows for recording of film viacurrently available technology.

FIG. 1D shows another alternative family of aspect ratios and imageframe sizes in pixels. The internal production storage format 206 hasframe size 1280×960 with aspect ratio 4:3 as employed in conventionaltelevision formats such as NTSC or PAL, and may be trimmed of top andbottom panels to use as a 1280×720 image frame with aspect ratio of16:9. After a 2:1 expansion/re-sizing, the intermediate format 208 isavailable, sizing to the alternative film format 209, with frame size5120×3840 and the same 4:3 aspect ratio, allows for recording of filmvia currently available technology.

Alternative implementations may employ different frame size (in pixels),aspect ratios, or frame rates, and these variations should be consideredto be within the scope of the invention.

FIG. 7 shows an implementation involving one possible choice for imagesizes, aspect ratios, and frame rates to provide a universal televisionproduction system. As shown, signals are provided from any of severalsources, including conventional broadcast signals 210, satellitereceivers 212, and interfaces to a high bandwidth data network 214.These signals would be provided to the digital tuner 218 and anappropriate adapter unit 220 for the data network or “informationsuperhighway” before being supplied to the decompression processor 222.The processor 222 provides any necessary data de-compression and signalconditioning for the various signal sources, and preferably isimplemented as a plug-in circuit board for a general-purpose computer,though the digital tuner 218 and the adapter 220 optionally may beincluded as part of the existing hardware.

The output of processor 222 is provided to the internal data bus 226.The system microprocessor 228 controls the data bus, and is providedwith 16 to 64 MB of RAM 230 ad up to 64 Mb of ROM 232. Thismicroprocessor could be implemented using one of the units previouslydescribed, such as the PowerPC 604 or PowerPC 620. A hard disk drivecontroller 234 provides access to various storage means, including, forexample, an internal hard disk drive unit 236, a removable hard diskdrive unit 238, or a tape drive 240; these storage units also enable thePC to function as a video recorder, as described above. A graphicprocessor 242, comprising dedicated hardware which optionally beimplemented as a separate plug-in circuit board, performs the imagemanipulations required to convert between the various frame sizes (inpixels), aspect ratios, and frame rates. This graphics processor uses 16to 32 MB of DRAM, and 2 to 8 MB of VRAM, depending on the type ofdisplay output desired. For frame size of 1280×720 with an aspect ratio16:9, the lower range of DRAM and VRAM will be sufficient, but for aframe size of 2048×1152, the higher range of DRAM and VRAM is required.In general, the 1280×720 size is sufficient for conventional“multi-sync”, computer display screens up to 20 inches, and the2048×1152 size is appropriate for conventional “multi-sync” computerdisplay screens up to 35 inches. Analog video outputs 244 are availablefor these various display units. Using this system, various formats maybe displayed, including (for 25 fps, shown by speeding up 24 fpssignals) 768×576 PAL/SECAM, 1024×576 wide-screen, and 2048×1152 HDTV,and (for 30 fps, shown by utilizing the well-known “3:2 pull-down”technique, and for 29.97 fps, shown by a slight slow-down in 30 fpssignals) 640×480 NTSC and 854×480 wide-screen, and 1280×720 USA and1920×1080 NHK (Japan) HDTV. While most NTSC monitors will synchronize toa 30 fps signal, possibly requiring that the color subcarrier frequencybe adjusted, many PAL and SECAM monitors will not accept a 24 fpssignal. In this case, more sophisticated frame-rate conversiontechniques may be required for viewing live broadcasts, since the 24 fpsinput signal rate cannot keep pace with the 25 fps display rate.However, in practice it is anticipated that future television sets willincorporate “multi-sync” designs that eliminate this potential problem.

Having described the invention, we claim:
 1. A multi-format audio/videoproduction system adapted for use with a display device, comprising:means to receive an input a signal representative of an audio/videoinput program having audio and video components, and wherein the videocomponent is received in one of a plurality of display formats withoutredundant frames or fields; a graphics processor connected to receivethe audio/video program audio and video components and convert thedisplay format of the input program into an intermediate productionformat, the graphics processor including: having a frame rate of 24 or25 frames per second (fps); a standard/widescreenan interface unitoperative to convert the video program in the production format into anoutput signal representative of a standard/widescreen formatted program,and a high-definition television (HDTV) interface unit operative toconvert the video program in the production format into an output signalrepresentative of an HDTV-formatted program; an output format;high-capacity video storage means; an operator interface; and acontroller in operative communication with the means to receive theinput signal, the graphics processor, the high-capacity video storagemeans and the operator interface, whereby commands entered by anoperator through the interface cause the following functions to beperformed: (a) the conversions of an audio/video the input program intothe production format, (b) storage of a program in the production formatin the high-capacity video storage means, and (c) the conversion of aprogram in the production format into a standard/widescreen program inthe output format, either directly from the means to receive the inputsignal or from the high-capacity video storage means, and (d) theconversion of a program in the production format into an HDTV program,either directly from the means to receive an input signal or from thehigh-capacity video storage means .
 2. The multi-format audio/videoproduction system of claim 1, the graphics processor further including afilm output video interface, the controller further being operative, inresponse to a command entered by an operator, to convert the videoprogram in the input format into an output signal for photographicproduction, either directly from the means to receive the input signalor from the high-capacity video storage means.
 3. The multi-formataudio/video production system of claim 1, including input and outputsignals compatible with any of the following standard formats: RGB, YIQ,YUV, and Y/R-Y/B-Y.
 4. The multi-format audio/video production system ofclaim 1, including input and output signals compatible with a videostandard utilizing separate luminance and chrominance component videosignals.
 5. The multi-format audio/video production system of claim 1,wherein the means to receive an input signal representative of a videoprogram includes a digital video camera including: a plurality of one ormore image sensors; an analog-to-digital converter circuit connected tothe output of each image sensor to generate a digital signalrepresentative of the sensed image; and a digital signal processorconfigured to receive the digital signal from each analog-to-digitalconverter circuit and generate a digital video output signal in apredetermined input format for processing by one or more of theinterface units comprising the graphics processor.
 6. The multi-formataudio/video production system of claim 5, wherein the digital videocamera uses two charge-coupled-device image sensors, one associated withluminance, the other associated with chrominance.
 7. The multi-formataudio/video production system of claim 1 wherein the means to receive avideo program includes a removeable high-capacity magnetic storagemedium.
 8. The multi-format audio/video production system of claim 1wherein, in the event that a change in aspect ratio results from any ofthe format conversions a conversion, the controller further is operativeto cause the change in aspect ratio to be visibly evident on the displaydevice.
 9. The multi-format audio/video production system of claim 1wherein the graphics processor interface unit is operative to convert a24 frame-per-second intermediate production format input signal into a30 frame-per-second NTSC-compatible format output signal.
 10. Themulti-format audio/video production system of claim 1 wherein thegraphics processor interface unit is operative to convert a 24frame-per-second intermediate production format input signal into a 25frame-per-second PAL/SECAM-compatible format output signal.
 11. Themulti-format audio/video production system of claim 1 wherein thegraphics processor interface unit is operative to convert a 24frame-per-second intermediate production format input signal into anHDTV-compatible format output signal.
 12. The multi/format audio/videoproduction system of claim 1, including means to receive an RGB videosignal having a chrominance bandwidth and a luminance bandwidth, andwherein the HDTV interface further provides means for reducing thechrominance bandwidth of the RGB video signal without reducing itsluminance bandwidth, the HDTV interface including: three low-passfilters, one associated with each of the R, G, and B components of theRGB video signal to remove all frequency components above a specifiedfrequency; an RGB-to-Y matrix circuit connected to receive each of theR, G, and B components, the RGB-to-Y matrix circuit being operative tocombine the signals in predetermined proportions and produce a singleluminance signal, Y; a high-pass filter connected to the output of theRGB-to-Y matrix circuit to filter the Y signal to remove all frequencycomponents below a specified frequency; a Y-to-RGB matrix circuitconnected to the output of the high-pass filter, the Y-to-RGB matrixcircuit being operative to separate the high-pass-filtered Y signal intoR′, G′ and B′ components in the same proportion as previously combinedby the RGB-to-Y matrix circuit; three mixers, each adapted to receive anR/R′, G/G′ and B/B′ pair, respectively, each mixer being operative tomix the signals of its respective input pairs and generate R″, G″ and B″signals having full luminance bandwidth and reduced chrominancebandwidth.
 13. The multi-format audio/video production system of claim1, the graphics processor further including means for transferring aprogram into in the intermediate production format to a remote locationequipped with one or more of the interface units.
 14. A multi-formataudio/video production system forming part of a general-purpose computerplatform having a user configured for use with an operator input andcolor display, the system comprising: meansan input to receive an inputavideo program in one of a plurality of input formatshaving no addedredundant frames or fields; a removable high-capacity video storagemeans;medium; and meansa first video processor operative to convert theinputvideo program into a 24 frames-per-second (fps)an intermediateproduction format, if not already in such a formathaving a frame rate ofsubstantially 24 frames per second (fps), for storage within thehigh-capacity video storage means and for review on the color display onthe removable medium; and meansa second video processor operative toconvert the program in the intermediate production format into one ormore of the following output formats, either directly from the input orfrom storagethe removable medium: NTSC at substantially 30 fps,PAL/SECAM at 25 fps, HDTV at 24, 25 or substantially 30 fps, and HDTV at30 fps, and film-compatible video at substantially 24 fps.
 15. Themulti-format audio/video production system of claim 14 wherein the meansto convert the production format into one or more of the output formatsincludes interpolation means to expand the number of pixels associatedwith the production format.
 16. The multi-format audio/video productionsystem of claim 14 wherein the means to convert the production versioninto one or more of the output formats includes image sequencing meansto convert the 24 fps production format into a 30 fps output format. 17.The multi-format audio/video production system of claim 14 wherein themeans to convert the production format into one or more of the outputformats includes means to increase the frame rate from the 24 fpsproduction format frame rate to a 25 fps output frame rate.
 18. Themulti-format audio/video production system of claim 14, including outputformats having the following image dimensions in pixels: 720×480,720×576, 1024×576, 1024×768, 1280×720, and 1080×960 1920×1080.
 19. Themulti-format audio/video production system of claim 14 wherein the meansto convert the production format into one or more of the output formatsincludes means to increase the frame rate from the 24 frames per secondproduction frame to an output having a frame rate of substantially 30frames per second.
 20. In an enhanced personal computer having a colormonitor, the A method of producing processing a video program,comprising the steps of: receiving an input video program having anaudio component and a video component without any added redundant framesor fields; converting the input video component of the input programinto a an internal production format having a predetermined frame rateof substantially 24 frames per second (fps) and an image dimension inpixels, when the program is not received in such a format; providing ahigh-capacity digital audio/video storage means storing the program inthe production format in the high-capacity storage means medium, andstoring the program in the production format; displaying the videoprogram on the color monitor using the predetermined frame rate andimage dimensions in pixels, including cropped versions of the program,with the extent of the cropping being visually evident on the monitor;accessing the program in the production format from the high-capacitystorage means medium; and manipulating the program to create a desirededited version of the program in an output format, including an outputformat having a frame rate and image dimensions in pixels different fromthat of the production format; and outputting the desired edited versionof the program in the output format. greater than or equal to the framerate of the production format.
 21. The method of claim 20, wherein thestep of manipulating the video program to create a desired editedversion of the program in a final format includes using animage-sequencing technique to convert from the production format at 24frames per second to produce an edited version of the program in a finalformat at 30 frames per second.
 22. The method of claim 20, wherein thestep of manipulating the video program to create a desired editedversion of the program in a final format includes the step ofinterpolating to produce an edited version of the program in a finalformat having pixel dimensions greater than that of the productionformat.
 23. The method of claim 20, wherein the step of manipulating thevideo program to create a desired edited version of the program in afinal format includes the step of increasing frame rate to produce anedited version of the program in a final format having a 25frame-per-second rate.
 24. The method of claim 20 wherein the step ofmanipulating the video program to create a desired edited version of theprogram in an output format includes creating a program having one ofthe following image dimensions in pixels: 720×480, 720×576, 1024×576,1024×768, 1280×720, and 1080×960. 1920×1080.
 25. The method of claim 20,wherein the step of converting the input video program into a productionformat includes converting the input video program into a productionformat characterized in having 24 frames per second.
 26. Themulti-format production system of claim 14 , wherein the high-capacityvideo storage means is a magnetic-disc-based medium.
 27. Themulti-format production system of claim 14 , wherein the high-capacityvideo storage means is an optical-disc-based medium.
 28. Themulti-format production system of claim 14 , wherein the high-capacityvideo storage means is a magneto-optical-disc-based medium.
 29. Themulti-format production system of claim 14 , wherein the high-capacityvideo storage means is a magnetic tape-based medium.
 30. Themulti-format production system of claim 14 , wherein the high-capacityvideo storage means is a multiple frame rate of 24, 25 or 30 fps. 31.The method of claim 20, further including the step of viewing thedesired version of the program in the output format at a locationdifferent from the one used to store the program on the high-capacitymedium.
 32. The multi-format production system of claim 1 , wherein theinterface unit is operative to convert the video program in theproduction format into an output format which is different from theformat of the input program.
 33. The multi-format production system ofclaim 14 , wherein the first and second video processors are elements ofthe same graphics processor.
 34. The multi-format production system ofclaim 14 , wherein the first and second video processors are physicallyremote from one another.
 35. The multi-format production system of claim20 , wherein the desired version of the program in the output format hasan image dimension in pixels which is different from that of theproduction format.
 36. The multi-format production system of claim 20 ,wherein the step of accessing the program in the production formatoccurs remotely from the step of converting the video component of theinput program into the internal production format.
 37. The multi-formatproduction system of claim 20 , wherein the step of providing ahigh-capacity digital audio/video storage medium includes providing amedium which is randomly accessible.